Dynamic self-configuring metering network

ABSTRACT

A dynamic self-configuring system for collecting metering data comprises a collector meter. The collector meter scans for meters that are operable to directly communicate with the collector and registers such meters as level one meters. The collector transmits instructions to the level one meters to scan for meters that are operable to directly communicate with the level one meters. The collector registers meters that respond as level two meters.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.10/185,664, filed Jun. 27, 2002, now U.S. Pat. No. 7,119,713 andentitled “Dynamic Self-Configuring Metering Network,” the contents ofwhich are hereby incorporated by reference in their entirety.

FIELD OF THE INVENTION

The present invention relates to metering systems, and moreparticularly, to wireless networks for gathering metering data.

BACKGROUND

The collection of meter data from electrical energy, water, and gasmeters has traditionally been performed by human meter-readers. Themeter-reader travels to the meter location, which is frequently on thecustomer's premises, visually inspects the meter, and records thereading. The meter-reader may be prevented from gaining access to themeter as a result of inclement weather or, where the meter is locatedwithin the customer's premises, due to an absentee customer. Thismethodology of meter data collection is labor intensive, prone to humanerror, and often results in stale and inflexible metering data.

Some meters have been enhanced to include a one-way radio transmitterfor transmitting metering data to a receiving device. A personcollecting meter data that is equipped with an appropriate radioreceiver need only come into proximity with a meter to read the meterdata and need not visually inspect the meter. Thus, a meter-reader maywalk or drive by a meter location to take a meter reading. While thisrepresents an improvement over visiting and visually inspecting eachmeter, it still requires human involvement in the process.

An automated means for collecting meter data involves a fixed wirelessnetwork. Devices such as, for example, repeaters and gateways arepermanently affixed on rooftops and pole-tops and strategicallypositioned to receive data from enhanced meters fitted withradio-transmitters. Data is transmitted from the meters to the repeatersand gateways and ultimately communicated to a central location. Whilefixed wireless networks greatly reduce human involvement in the processof meter reading, such systems require the installation and maintenanceof a fixed network of repeaters, gateways, and servers. Identifying anacceptable location for a repeater or server and physically placing thedevice in the desired location on top of a building or utility pole is atedious and labor-intensive operation. Furthermore, each meter that isinstalled in the network needs to be manually configured to communicatewith a particular portion of the established network. When a portion ofthe network fails to operate as intended, human intervention istypically required to test the effected components and reconfigure thenetwork to return it to operation. Thus, while existing fixed wirelesssystems have reduced the need for human involvement in the dailycollection of meter data, such systems require substantial humaninvestment in planning, installation, and maintenance and are relativelyinflexible and difficult to manage.

SUMMARY

A dynamic self-configuring system for collecting meter data is disclosedherein. In an illustrative embodiment, a plurality of meter devices,which operate to track usage of a service or commodity such as, forexample, electricity, water, and gas, are operable to wirelesslycommunicate. One of the meter devices, which is referred to as acollector, broadcasts messages to identify one or more of the meterswith which it can directly communicate. The meters with which thecollector is operable to directly communicate may be referred to aslevel one meters. Data designating these meters as level one meters isstored on the collector and the level one meters.

The collector communicates instructions to the level one meters to scanfor meters that are operable to directly communicate with the level onemeters. Meters that directly communicate with the level one meters maybe referred to as level two meters. Data identifying the level twometers and the communication path to the level two meters is stored onthe collector and the level two meters.

The collector continues the process of scanning the last defined levelof meters for new meters that communicate with the last defined level.This process gradually provides identification of the meters in thenetwork and the paths by which to communicate with each meter.Additionally, when new meters are added to the network, they areidentified via subsequent scans.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features of systems and methods for gathering metering data arefurther apparent from the following detailed description of exemplaryembodiments taken in conjunction with the accompanying drawings, ofwhich:

FIG. 1 is a diagram of a wireless system for collecting meter data;

FIG. 2 depicts a flow chart of a process for exception handling;

FIGS. 3A and 3B depicts a flow chart of a process for registering nodeswith a collector;

FIG. 4 depicts a flow chart of a process for registering a newly addedmeter;

FIG. 5 depicts a flow chart of a process for switching the communicationpath for a registered node to a new collector;

FIG. 6 depicts a flow chart of a process for reading usage data;

FIG. 7 depicts a flow chart of a process for reading data from a one-waymeter;

FIG. 8 depicts a block diagram of a meter suitable for use with thedisclosed embodiments; and

FIG. 9 is a diagram of a general purpose computing device.

DETAILED DESCRIPTION

Exemplary systems and methods for gathering meter data are describedbelow with reference to FIGS. 1-9. It will be appreciated by those ofordinary skill in the art that the description given herein with respectto those figures is for exemplary purposes only and is not intended inany way to limit the scope of potential embodiments.

Generally, a plurality of meter devices, which operate to track usage ofa service or commodity such as, for example, electricity, water, andgas, are operable to wirelessly communicate with each other. A collectormeter is operable to automatically identify and register meters forcommunication with the collector meter. When a meter is installed, themeter becomes registered with the collector that can provide acommunication path to the meter. The collectors receive and compilemetering data from a plurality of meter devices via wirelesscommunications. A communications server communicates with the collectorsto retrieve the compiled meter data.

FIG. 1 provides a diagram of an exemplary metering system 110. System110 comprises a plurality of meters 114, which are operable to sense andrecord usage of a service or commodity such as, for example,electricity, water, or gas. Meters 114 may be located at customerpremises such as, for example, a home or place of business. Meters 114comprise an antenna and are operable to transmit data, including serviceusage data, wirelessly. Meters 114 may be further operable to receivedata wirelessly as well. In an illustrative embodiment, meters 114 maybe, for example, a electrical meters manufactured by ABB Incorporated.

System 110 further comprises collectors 116. Collectors 116 are alsometers operable to detect and record usage of a service or commoditysuch as, for example, electricity, water, or gas. Collectors 116comprise an antenna and are operable to send and receive datawirelessly. In particular, collectors 116 are operable to send data toand receive data from meters 114. In an illustrative embodiment, meters114 may be, for example, an electrical meter manufactured by ABBIncorporated.

A collector 116 and the meters 114 for which it is configured to receivemeter data define a subnet 120 of system 110. For each subnet 120, datais collected at collector 116 and periodically transmitted tocommunication server 122. Communication server 122 stores the data foranalysis and preparation of bills. Communication server 122 may be aspecially programmed general purpose computing system and maycommunicate with collectors 116 wirelessly or via a wire line connectionsuch as, for example, a dial-up telephone connection or fixed wirenetwork.

Thus, each subnet 120 comprises a collector 116 and one or more meters114, which may be referred to as nodes of the subnet. Typically,collector 116 directly communicates with only a subset of the pluralityof meters 114 in the particular subnet. Meters 114 with which collector116 directly communicates may be referred to as level one meters 114 a.The level one meters 114 a are said to be one “hop” from the collector116. Communications between collector 116 and meters 114 other thanlevel one meters 114 a are relayed through the level one meters 114 a.Thus, the level one meters 114 a operate as repeaters for communicationsbetween collector 116 and meters 114 located further away in subnet 120.

Each level one meter 114 a directly communicates with only a subset ofthe remaining meters 114 in the subnet 120. The meters 114 with whichthe level one meters 114 a directly communicate may be referred to aslevel two meters 114 b. Level two meters 114 b are one “hop” from levelone meters 114 a, and therefore two “hops” from collector 116. Level twometers 114 b operate as repeaters for communications between the levelone meters 114 a and meters 114 located further away from collector 116in the subnet 120.

While only three levels of meters are shown (collector 114, first level114 a, second level 114 b) in FIG. 1, a subnet 120 may comprise anynumber of levels of meters 114. For example, a subnet 120 may compriseone level of meters but might also comprise eight or more levels ofmeters 114. In an embodiment wherein a subnet comprises eight levels ofmeters 114, as many as 512 meters might be registered with a singlecollector 116.

Each meter 114 and collector 116 that is installed in the system 110 hasa unique identifier stored thereon that uniquely identifies the devicefrom all other devices in the system 110. Additionally, meters 114operating in a subnet 120 comprise information including the following:data identifying the collector with which the meter is registered; thelevel in the subnet at which the meter is located; the repeater meterwith which the meter communicates to send and receive data to thecollector; an identifier indicating whether the meter is a repeater forother nodes in the subnet; and if the meter operates as a repeater, theidentifier that uniquely identifies the repeater within the particularsubnet, and the number of meters for which it is a repeater. Collectors116 have stored thereon all of this same data for all meters 114 thatare registered therewith. Thus, collector 116 comprises data identifyingall nodes registered therewith as well as data identifying theregistered path by which data is communicated with each node.

Generally, collector 116 and meters 114 communicate with and amongst oneanother using any one of several robust wireless techniques such as, forexample, frequency hopping spread spectrum (FHSS) and direct sequencespread spectrum (DSSS).

For most network tasks such as, for example, reading data, collector 116communicates with meters 114 in the subnet 120 using point-to-pointtransmissions. For example, a message or instruction from collector 116is routed through a defined set of meter hops to the desired meter 114.Similarly, a meter 114 communicates with collector 117 through the sameset of meter hops, but in reverse.

In some instances, however, collector 117 needs to quickly communicateinformation to all meters 114 located in its subnet 120. Accordingly,collector 117 may issue a broadcast message that is meant to reach allnodes in the subnet 120. The broadcast message may be referred to as a“flood broadcast message.” A flood broadcast originates at collector 116and propagates through the entire subnet 120 one level at a time. Forexample, collector 116 may transmit a flood broadcast to all first levelmeters 114 a. The first level meters 114 a that receive the message picka random time slot and retransmit the broadcast message to second levelmeters 114 b. Any second level meter 114 b can accept the broadcast,thereby providing better coverage from the collector out to the endpoint meters. Similarly, the second level meters 114 b that receive thebroadcast message pick a random time slot and communicate the broadcastmessage to third level meters. This process continues out until the endnodes of the subnet. Thus, a broadcast message gradually propagates outthe subnet 120.

The flood broadcast packet header contains information to prevent nodesfrom repeating the flood broadcast packet more than once per level. Forexample, within a flood broadcast message, a field might exist thatindicates to meters/nodes which receive the message, the level of thesubnet the message is located; only nodes at that particular level mayre-broadcast the message to the next level. If the collector broadcastsa flood message with a level of 1, only level 1 nodes may respond. Priorto re-broadcasting the flood message, the level 1 nodes increment thefield to 2 so that only level 2 nodes respond to the broadcast.Information within the flood broadcast packet header ensures that aflood broadcast will eventually die out.

Generally, a collector 116 issues a flood broadcast several times, e.g.five times, successively to increase the probability that all meters inthe subnet 120 receive the broadcast. A delay is introduced before eachnew broadcast to allow the previous broadcast packet time to propagatethrough all levels of the subnet.

Meters 114 may have a clock formed therein. However, meters 114 oftenundergo power interruptions that can interfere with the operation of anyclock therein. Accordingly, the clocks internal to meters 114 cannot berelied upon to provide an accurate time reading. Having the correct timeis necessary, however, when time of use metering is being employed.Indeed, in an embodiment, time of use schedule data may also becomprised in the same broadcast message as the time. Accordingly,collector 116 periodically flood broadcasts the real time to meters 114in subnet 120. Meters 114 use the time broadcasts to stay synchronizedwith the rest of the subnet 120. In an illustrative embodiment,collector 116 broadcasts the time every 15 minutes. The broadcasts maybe made near the middle of 15 minute clock boundaries that are used inperforming load profiling and time of use (TOU) schedules so as tominimize time changes near these boundaries. Maintaining timesynchronization is important to the proper operation of the subnet 120.Accordingly, lower priority tasks performed by collector 116 may bedelayed while the time broadcasts are performed.

In an illustrative embodiment, the flood broadcasts transmitting timedata may be repeated, for example, five times, so as to increase theprobability that all nodes receive the time. Furthermore, where time ofuse schedule data is communicated in the same transmission as the timingdata, the subsequent time transmissions allow a different piece of thetime of use schedule to be transmitted to the nodes.

Exception messages are used in subnet 120 to transmit unexpected eventsthat occur at meters 114 to collector 116. In an embodiment, the first 4seconds of every 32-second period are allocated as an exception windowfor meters 114 to transmit exception messages. Meters 114 transmit theirexception messages early enough in the exception window so the messagehas time to propagate to collector 116 before the end of the exceptionwindow. Collector 116 may process the exceptions after the 4-secondexception window. Generally, a collector 116 acknowledges exceptionmessages, and collector 116 waits until the end of the exception windowto send this acknowledgement.

In an illustrative embodiment, exception messages are configured as oneof three different types of exception messages: local exceptions, whichare handled directly by the collector 116 without intervention fromcommunication server 122; an immediate exception, which is generallyrelayed to communication server 122 under an expedited schedule; and adaily exception, which is communicated to the communication server 122on a regular schedule.

FIG. 2 presents a flowchart of a process employed by collector 116 forhandling these exceptions. At step 210, the exception is received atcollector 116. At step 212, collector 116 identifies the type ofexception that has been received. If a local exception has beenreceived, at step 214, collector 116 takes an action to remedy theproblem. For example, when collector 116 receives an exceptionrequesting a node scan request such as discussed below, collector 116transmits a command to initiate a scan procedure to the meter 114 fromwhich the exception was received.

If an immediate exception type has been received, at step 220, collector116 makes a record of the exception. An immediate exception mightidentify, for example, that there has been a power outage. Collector 116may log the receipt of the exception in one or more tables or files. Inan illustrative example, a record of receipt of an immediate exceptionis made in a table referred to as the “Immediate Exception Log Table.”

At step 222, collector 116 waits a set period of time before takingfurther action with respect to the immediate exception. For example,collector 116 may wait 64 seconds. This delay period allows theexception to be corrected before communicating the exception tocommunication server 122. For example, where a power outage was thecause of the immediate exception, collector 116 may wait a set period oftime to allow for receipt of a message indicating the power outage hasbeen corrected.

If at step 224 the exception has not been corrected, at step 226,collector 116 communicates the immediate exception to communicationserver 122. For example, collector 116 may initiate a dial-up connectionwith communication server 122 and download the exception data. Afterreporting an immediate exception to communications server 122, collector116 may delay reporting any additional immediate exceptions for a periodof time such as ten minutes. This is to avoid reporting exceptions fromother meters 114 that relate to, or have the same cause as the exceptionthat was just reported.

If a daily exception was received, at step 230, the exception isrecorded in a file or a database table. Generally, daily exceptions areoccurrences in the subnet 120 that need to be reported to communicationserver 122, but are not so urgent that they need to be communicatedimmediately. For example, when collector 116 registers a new meter 114in subnet 120, collector 116 records a daily exception identifying thatthe registration has taken place. In an illustrative embodiment, theexception is recorded in a database table referred to as the “DailyException Log Table.” At step 232, collector 116 communicates the dailyexceptions to communications server 122. Generally, collector 116communicates the daily exceptions once every 24 hours.

According to an aspect of the disclosed system 110, a collector 116 maydynamically identify meters 114 that are operable to communicate with itin a subnet 120 as well as identify more efficient communication pathsfor previously registered meters. For example, when a collector 116 isinitially brought into system 110, it needs to identify and registermeters in its subnet 120. A “node scan” refers to a process ofcommunication between connectors 116 and meters 114 whereby a collectormay identify and register new nodes in a subnet 120 and allow previouslyregistered nodes to switch paths. A collector 116 can implement a nodescan on the entire subnet, referred to as a “full node scan,” or a nodescan can be performed on specially identified nodes, referred to as a“node scan retry.”

A full node scan may be performed, for example, when a collector isfirst installed. The collector 116 must identify and register nodes fromwhich it will collect usage data. FIGS. 3A and 3B depict a flow chart ofa process for performing a “full node scan.” As shown, at step 310, thecollector 116 initiates the node scan by broadcasting a request, whichmay be referred to as a Node Scan Procedure request. Generally, the NodeScan Procedure request directs that all unregistered meters 114 or nodesthat receive the request respond to the collector 116. The request maycomprise information such as the unique address of the collector thatinitiated the procedure. The signal by which collector 116 transmitsthis request may have limited strength and therefore is detected atmeters 114 that are in proximity of collector 116. Meters 114 thatreceive the Node Scan Procedure request respond by transmitting theirunique identifier as well as other data.

Collector 116 receives a response from one of the meters 114 at step312. At step 313, collector 116 identifies a received signal strength(RSSI) value for the response from meter 114. At step 314, collector 116stores in memory the meter's 114 unique identifier along with thecorresponding RSSI value.

Preferably, collector 116 attempts to register meters 114 that will havea reliable data communication path. Accordingly, at step 316, collector116 compares the RSSI value of the node scan response with a selectedthreshold value. For example, the threshold value may be −60 dBm. RSSIvalues above this threshold are sufficiently reliable. Collector 116maintains a list of meters 114 that responded but which do not satisfythe RSSI threshold. For example, a database table referred to as theStraggler table may be employed to store for each meter that respondedto a Node Scan Response and did not meet the RSSI value, the meter'sunique identifier and the RSSI value of the response. Accordingly, if atstep 316 the RSSI value is not greater than the established threshold,at step 318, collector 116 updates its list to include the meter'sunique identifier and RSSI value. Thereafter, processing continues atstep 326.

If at step 316, the RSSI value exceeds the threshold, at step 324,collector 116 registers the node. Registering a meter 114 comprisesupdating a list of the registered nodes at collector 116. For example,the list may be updated to identify the meter's system-wide uniqueidentifier and the communication path to the node. Collector 116 alsorecords the meter's level in the subnet (i.e. whether the meter is alevel one node, level two node, etc.), whether the node operates as arepeater, and if so, the number of meters for which it operates as arepeater. Upon initialization, the data indicates the node is not arepeater and the number of meters for which it operates as a repeater iszero. The registration process further comprises transmittingregistration information to the meter 114. For example, collector 116forwards to meter 114 an indication that it is registered, the uniqueidentifier of the collector with which it is registered, the level themeter exists at in the subnet, and the unique identifier of the meterwith which it should communicate data. The meter stores this data andbegins to operate as part of the subnet by responding to commands fromits collector 116.

At step 326, collector 116 determines if there are additional responsesto the node scan request. If so, processing continues at step 314.

Steps 310 through 326 may be performed several times so as to insurethat all meters 114 that may receive the Node Scan Procedure, have anopportunity for their response to be received at collector 116.Accordingly, at step 328, collector 116 determines whether the Node Scanshould be implemented again. Generally, this is determined by comparingthe number of times the steps have been completed with a predefinedlimit. If the limit has not been met, processing continues at step 310.If the limit has been met, a first portion of the node scan procedure iscomplete. It is presumed that all first level meters 114 have beenidentified and registered at this point in the process. The Stragglerlist may identify one or more meters 114 that did not satisfy the RSSIthreshold. The node scan process continues by performing a similarprocess as that described above at each of the now registered level onenodes. This process results in the identification and registration oflevel two nodes. After the level two nodes are identified, a similarnode scan process is performed at the level two nodes to identify levelthree nodes, and so on.

FIG. 3B is a flow chart of the process for identifying and registeringmeters located above the level one meters. At step 340, collector 116transmits a command, which may be referred to as an Initiate Node ScanProcedure, to the first of the meters 114 registered at steps 310through 328, to initiate a node scan process at the particular meter114. The request comprises several data items that the receiving metermay use in completing the node scan. For example, the request maycomprise the number of timeslots available for responding nodes, theunique address of the collector that initiated the request, and ameasure of the reliability of the communications between the target nodeand the collector. As described below in connection with FIG. 4, themeasure of reliability is employed during a process for identifying morereliable paths for previously registered nodes.

The meter that receives the Initiate Node Scan Response request respondsby performing a node scan process similar to that described above atsteps 310 through 328. More specifically, the meter broadcasts a requestto which all unregistered nodes respond. The request comprises thenumber of timeslots available for responding nodes (which is used to setthe period for the node to wait for responses), the unique address ofthe collector that initiated the node scan procedure, a measure of thereliability of the communications between the sending node and thecollector (which is used in the process of determining whether a meter'spath may be switched as defined below in connection with FIG. 5), thelevel within the subnet of the node sending the request, and an RSSIthreshold (which is used in the process of determining whether aregistered meter's path may be switched as described below in connectionwith FIG. 4). The meter issuing the node scan request waits for andreceives responses. For each response, the meter stores in memory theunique identifier and the RSSI value of the response. At step 342,collector 116 waits while the response are collected at the meter thatissued the node scan. At step 344, collector 116 retrieves the nodeinformation that has been collected by the meter. At step 346, collector116 parses the information and selects one of the meters or potentialnodes in the list of retrieved data.

Collector 116 attempts to register meters 114 that will have a reliabledata communication path. Accordingly, at step 348, collector 116compares the RSSI value for the selected meter 114 with a selectedthreshold value. If the RSSI value is not greater than the thresholdvalue, at step 350, collector 116 determines if the particular meter waspreviously identified as having responded to a Node Scan Responserequest but having not met the RSSI threshold. Specifically, collector116 may refer to its Straggler table or similar file where it maintainsa list of meters 114 that meet this criteria. If so, at step 352,collector 116 compares the RSSI value with the previously stored value.If the new RSSI value is greater than the previous value, at step 354,collector updates the Straggler table to identify the new RSSI value andthe new communication path. If at step 352, the new RSSI value is notgreater than the previous value, processing continues at step 362. If atstep 350, it is determined that the particular meter 114 is not in theStraggler table, processing continues at step 354, where the Stragglertable is updated to reflect the meter identifier, the communication pathto is this meter and the RSSI value. Thereafter, processing continues atstep 362.

If at step 348, the RSSI value exceeded the threshold, at step 360,collector 116 registers the node. Registering a meter 114 comprisesupdating a list of the registered nodes at collector 116. For example,the list may be updated to identify the meter's unique identifier andthe level of the meter in the subnet, i.e. whether the meter is a levelone node, level two node, etc. Additionally, the collector's 116registration information is updated to reflect that the meter 114 fromwhich the scan process was initiated is identified as a repeater for thenewly registered node. The registration process further comprisestransmitting information to the newly registered meter as well as themeter that will serve as a repeater for the newly added node. Forexample, the node that issued the node scan response request is updatedto identify that it operates as a repeater and, if it was previouslyregistered as a repeater, increments a data item identifying the numberof nodes for which it serves as a repeater. Thereafter, collector 116forwards to the newly registered meter an indication that it isregistered, an identification of the collector 116 with which it isregistered, the level the meter exists at in the subnet, and the uniqueidentifier of the node with which it communicates to forward informationto collector 116.

At step 362, collector 116 determines if there are additional nodesidentified in the information retrieved from the meter 114 thatperformed the node scan request. If so, processing continues at step346.

If at step 362, there are no potential nodes to be evaluated, at step364, collector 116 determines if there are other registered nodes on thesame level that have not been directed to perform a node scan. Forexample, if level 1 nodes are being scanned for potential level 2 nodes,at step 364 collector 116 determines if there are any level 1 nodes thathave not yet performed a node scan procedure. If so, processingcontinues at step 340 wherein collector requests that a node scanprocedure be performed at the node.

If at step 364, all nodes at the level of the subnet under evaluationhave been reviewed, processing continues at step 368, with collector 116determining if there are registered meters at the next level of thesubnet. If so, processing continues at step 340 with node scans beingperformed at this next level.

If at step 368 there are no registered nodes at the next higher level,at step 370, collector 116 registers the nodes identified in the list ofmeters that have responded but did not meet the RSSI threshold. At thispoint in the process, presumably, the list comprises the best pathidentified for each of the unregistered meters that responded, even ifthat path does not meet the desired RSSI threshold. If during operationof the network, a meter registered in this manner fails to performadequately, it may be assigned a different path or possibly to adifferent collector as described below.

As previously mentioned, a full node scan may be performed when acollector 116 is first introduced to a network. At the conclusion of thefull node scan, a collector 116 will have registered a set of meters 114with which it communicates and reads metering data. Full node scansmight be periodically performed by an installed collector to identifynew meters 114 that have been brought on-line since the last node scanand to allow registered meters to switch to a different path.

In addition to the full node scan, collector 116 may also perform aprocess of scanning specific meters 114 in the subnet 120, which isreferred to as a “node scan retry.” For example, collector 116 may issuea specific request to a meter 114 to perform a node scan outside of afull node scan when on a previous attempt to scan the node, thecollector 116 was unable to confirm that the particular meter 114received the node scan request. Also, a collector 116 may request a nodescan retry of a meter 114 when during the course of a full node scan thecollector 116 was unable to read the node scan data from the meter 114.Similarly, a node scan retry will be performed when an exceptionprocedure requesting an immediate node scan is received from a meter114.

According to an aspect of the disclosed embodiment, system 110automatically reconfigures to accommodate a new meter 114 that may beadded. More particularly, the system identifies that the new meter hasbegun operating and identifies a path to a collector 116 that willbecome responsible for collecting the metering data. A flow chart of aprocess for adding a new meter is depicted in FIG. 4. As shown, at step410, the new meter broadcasts an indication that it is unregistered. Inone embodiment, this broadcast might be, for example, embedded in, orrelayed as part of a request for an update of the real time as describedabove. At step 412, the broadcast is received at one of the registeredmeters 114 in proximity to the meter that is attempting to register. Atstep 414, the registered meter 114 forwards the time to the meter thatis attempting to register. At step 416, the registered node alsotransmits an exception request to its collector 116 requesting that thecollector 116 implement a node scan, which presumably will locate andregister the new meter. At step 418, the collector 116 transmits arequest that the registered node perform a node scan. At step 420, theregistered node performs the node scan during which it requests that allunregistered nodes respond. At step 422, the newly added, unregisteredmeter responds to the node scan. At step 424, the unique identifier ofthe newly added node along with the RSSI value of its response arestored on the registered node. At step 426, collector 116 retrieves theresponse data. If at step 428 the RSSI value of the response from thenew meter exceeds the established RSSI threshold, at step 430 collector116 updates its data files to identify the new meter as being registeredand transmits a registration notification to the new meter. If at step428 the RSSI value does not exceed the threshold, the unique identifieris added to the list of unregistered nodes, at step 432. The newly addedmeter will continue to broadcast that it is unregistered and ultimatelywill be registered through a meter with which it satisfies the RSSIthreshold.

A collector 116 periodically retrieves meter data from the meters thatare registered with it. For example, meter data may be retrieved from ameter every 4 hours. Where there is a problem with reading the meterdata on the regularly scheduled interval, the collector will try to readthe data again before the next regularly scheduled interval.Nevertheless, there may be instances wherein the collector 116 is unableto read metering data from a particular meter 114 for a prolonged periodof time. The meters 114 store an indication of when they are read bycollector 116 and keep track of the time since their data has last beencollected by the collector 116. If the length of time since the lastreading exceeds a defined threshold such as for example, 18 hours,presumably a problem has arisen in the communication path between theparticular meter 114 and the collector 116. Accordingly, the meter 114changes its status to that of an unregistered meter and attempts tolocate a new path to a collector 116 via the process described above inconnection with FIG. 3. Thus, the exemplary system is operable todynamically reconfigure itself to address inadequacies in the system.

In some instances, while a collector 116 may be able to retrieve datafrom a registered meter 114 occasionally, the level of success inreading the meter may be inadequate. For example, if a collector 116attempts to read meter data from a meter 114 every 4 hours but is ableto read the data, for example, only 70 percent of the time or less, itmay be desirable to find a more reliable path for reading the data fromthat particular meter. Where the frequency of reading data from a meter114 falls below a desired frequency, the collector 116 transmits amessage to the meter 114 to respond to node scans going forward. Themeter 114 remains registered but will respond to node scans such as aredescribed above in connection with FIG. 3. If the meter 114 responds toa node scan procedure, the collector 116 recognizes the response asoriginating from a registered meter. The collector 116 verifies that theRSSI value of the node scan response exceeds the established threshold.If it does not, the potential path is not acceptable. However, if theRSSI threshold is met, the collector 116 initiates a qualificationprocedure whereby it makes several attempts to reach the meter throughthe potential path. If the collector is successful in establishingcommunication with the meter through the potential path more than anacceptable percentage of the time, e.g. 80 percent, then the collectorregisters the meter in the new path. The registration process comprisesupdating the collector 116 and meter 114 with data identifying therepeater with which the meter 114 will communicate. Additionally, if therepeater has not previously performed the operation of a repeater, therepeater would need to be updated to identify that it is a repeater.Likewise, the repeater with which the meter previously communicated isupdated to identify that it is no longer a repeater for the particularmeter 114.

In some instances, a more reliable communication path for a meter mayexist through a collector other than that with which the meter isregistered. A meter may automatically recognize the existence of themore reliable communication path, switch collectors, and notify theprevious collector that the change has taken place. FIG. 5 provides aflow chart of a method for switching the registration of a meter from afirst collector to a second collector. As shown, at step 510, aregistered meter 114 receives a node scan request from a collector 116other than that with which the meter is registered. Typically, aregistered meter 114 does not respond to node scan requests. However, ifthe request is likely to result in a more reliable transmission path,even a registered meter may respond. Accordingly, at step 512, the meterdetermines if the new collector offers a potentially more reliabletransmission path. For example, the meter 114 may determine if the pathto the potential new collector 116 comprises fewer hops than the path tothe collector with which the meter is registered. If not, the path maynot be more reliable and the meter 114 will not respond to the nodescan. The meter 114 might also determine if the RSSI of the node scanpacket exceeds an RSSI threshold identified in the node scaninformation. If so, the new collector may offer a more reliabletransmission path for meter data. If not, the transmission path is notacceptable and the meter does not respond. Additionally, if thereliability of communication between the potential new collector and therepeater that would service the meter meets a threshold established whenthe repeater was registered with its existing collector, thecommunication path to the new collector may be more reliable. If thereliability does not exceed this threshold, however, the meter 114 doesnot respond to the node scan.

If at step 512, it is determined that the path to the new collector maybe better than the path to its existing collector, at step 514, themeter 114 responds to the node scan. Included in the response isinformation regarding any nodes for which the particular meter mayoperate as a repeater. For example, the response might identify thenumber of nodes for which the meter serves as a repeater.

At step 516, collector 116 determines if it has the capacity to servicethe meter and any meters for which it operates as a repeater. If not,the collector 116 does not respond to the meter that is attempting tochange collectors. If, however, the collector 116 determines that it hascapacity to service the meter 114, at step 518, the collector 116 storesregistration information about the meter 114. At step 520, collector 116transmits a registration command to meter 114. At step 522, the meter114 updates its registration data to identify that it is now registeredwith the new collector. At step 524, collector 116 communicatesinstruction to the meter 114 to initiate a node scan request. Nodes thatare unregistered, or that had previously used meter 114 as a repeaterrespond to the request to identify themselves to collector 116. Thecollector registers these nodes as is described above in connection withregistering new meters/nodes.

Under some circumstances it may be necessary to change a collector. Forexample, a collector may be malfunctioning, and need to be takenoff-line. Accordingly, a new communication path must be provided forcollecting meter data from the meters serviced by the particularcollector. The process of replacing a collector is performed bybroadcasting a message to unregister, usually from a replacementcollector, to all of the meters that are registered with the collectorthat is being removed from service. According to an aspect of thedisclosed embodiment, registered meters may be programmed to onlyrespond to commands from the collector with which they are registered.Accordingly, the command to unregister may comprise the uniqueidentifier of the collector that is being replaced. In response to thecommand to unregister, the meters begin to operate as unregisteredmeters and respond to node scan requests. To allow the unregisteredcommand to propagate through the subnet, when a node receives thecommand it will not unregister immediately, but rather remain registeredfor a defined period, which may be referred to as the “Time to Live”.During this time to live period, the nodes continue to respond toapplication layer and immediate retries allowing the unregistrationcommand to propagate to all nodes in the subnet. Ultimately, the metersregister with the replacement collector as described above in connectionwith FIG. 3.

One of collector's 116 main responsibilities within subnet 120 is toretrieve metering data from meters 114. The self-configuring andself-healing characteristics of system 110 provide that collectors 116have improved reliability in reading usage data. Generally, meters 114store data regarding usage of electricity, gas, water, etc. in memory.Collector 116 periodically retrieves this data from nodes in its subnet120. In an embodiment, collector 116 has as a goal to obtain at leastone successful read of the metering data per day from each node in itssubnet. Collector 116 attempts to retrieve the data from all nodes inits subnet 120 at a configurable periodicity. For example, collector 116may be configured to attempt to retrieve metering data from meters 114in its subnet 120 once every 4 hours. FIG. 6 depicts a flow chart of aprocess for retrieving data from meters 114 in a subnet 120. As shown,at step 610, collector 116 identifies one of the meters 114 in itssubnet 120. For example, collector 116 reviews a list of registerednodes and identifies one for reading. At step 612, collector 116communicates a command to the particular meter 114 that it forward itsmetering data to the collector 116. If at step 614, the meter reading issuccessful and the data is received at collector 116, at step 616collector 116 determines if there are other meters that have not beenread during the present reading session. If so, processing continues atstep 610. However, if all of the meters 114 in subnet 120 have beenread, at step 618, collector waits a defined length of time, such as,for example, 4 hours, before attempting another read.

If at step 614, the meter data was not received at collector 116, atstep 620 collector 116 begins a retry procedure wherein it attempts toretry the data read from the particular meter. Collector 116 continuesto attempt to read the data from the node until either the data is reador the next subnet reading takes place. In an embodiment, collector 116attempts to read the data every 60 minutes. Thus, wherein a subnetreading is taken every 4 hours, collector 116 may issue three retriesbetween subnet readings.

The inability to read metering data may be the result of communicationfailures that can take place at the packet communication level. Forexample, if for each hop the probability of successful communications is95%, a level 8 node requires 16 message hops, which would result in a44% probability a successful round trip message. If 2 immediate retriesare used for each hop, the per hop probability increases from 95% to99.98% and the probability of a successful round trip message increasesto 99.8%. Accordingly, in an embodiment of the disclosed system, witheach successive retry to read data from a node, the number of packetlevel retries increases. For example, if during a normal read attemptone packet level retry is undertaken, when an application level retry toread the data is made by the collector, two or more packet level retriesmay be implemented. Thus, as the number of application level retriesincreases, so does the number of packet level retries. Furthermore, thenumber of packet level retries varies according to the level at whichthe particular meter 114 exists in the subnet 120. The higher the level,the greater the number of packet level retries. The table below listsexemplary packet level retries for various subnet levels and variousnumbers of prior application level retry attempts.

Application Layer Attempt 1 2 ≧3 Levels 1 and 2 1 2 3 Levels 3 and 4 2 34 Levels 5–6 2 3 4 Levels > 6 3 4 5

In an embodiment of system 120, meters 114 are typically two-waymeters—i.e. they are operable to both receive and transmit data.However, one-way meters that are operable only to transmit and notreceive data may also be deployed in the system 110. FIG. 7 provides aflow chart of a process for reading data from one-way meters deployed inthe system. As shown, at step 710 a one-way meter broadcasts their usagedata. At step 712, this data is received at one or more two-way metersthat are in proximity to the one-way meter. At step 714, the data isstored on the two-way meter, and designated as having been received fromthe one-way meter. At step 716, the data from the one-way meter iscommunicated to the collector with which the two-way meter isregistered. For example, when the collector reads the two-way meterdata, it recognizes the existence of meter data from the one-way meterand reads it as well. At step 718, after the data from the one-way meterhas been read, it is removed from memory.

A block diagram for an exemplary meter device operable to perform asmeter 114 or collector 116 as described above is depicted in FIG. 8. Asshown, meter device 810 comprises metering electronics 812 forphysically measuring the amount of a service or commodity that is used,and wireless communications electronics 814 for transmitting andreceiving data to other meter devices. Device 810 further comprisesmemory 816 for storing data and executable instructions for performingmethods as described above. Processor 818 is operable to execute theinstructions stored in memory 816. Device 810 may further comprisevisual display 818 for displaying metering data at device 810.Wire-based communications electronics 820 provides the capability tocommunicate with device 810 via means other than wirelessly. Forexample, wire-based communications electronics 820 may comprise a modemfor communicating over telephone lines or a network protocol transceiverfor communicating over a dedicated local area or wide area network.

FIG. 9 is a diagram of a generic computing device, which may be operableto perform the steps described above as being performed bycommunications server 122. As shown in FIG. 9, communications server 922includes processor 922, system memory 924, and system bus 926 thatcouples various system components including system memory 924 toprocessor 922. System memory 924 may include read-only memory (ROM)and/or random access memory (RAM). Computing device 920 may furtherinclude hard-drive 928, which provides storage for computer readableinstructions, data structures, program modules, data, and the like. Auser (not shown) may enter commands and information into the computingdevice 920 through input devices such as keyboard 940 or mouse 942. Adisplay device 944, such as a monitor, a flat panel display, or the likeis also connected to computing device 920. Communications device 943,which may be a modem, network interface card, or the like, provides forcommunications over a network. System memory 924 and/or hard-drive 928may be loaded with any one of several computer operating systems such asWINDOWS NT operating system, WINDOWS 2000 operating system, LINUXoperating system, and the like.

Those skilled in the art understand that processor readable instructionsfor implementing the above-described processes, such as those describedwith reference to FIGS. 2 through 7 can be generated and stored inprocessor-readable memory and processor-readable media such as amagnetic disk or CD-ROM. Further, a computing system such as thatdescribed with reference to FIG. 9 may be arranged with metering devicessuch as that described in FIG. 8, and the devices loaded withprocessor-readable instructions for performing the above describedprocesses. Specifically, referring to FIGS. 8 and 9, processors 922 and818 may be programmed to operate in accordance with the above-describedprocesses.

Thus, a dynamic self-configuring system for gathering metering data hasbeen disclosed. This novel system and the methods performed thereinprovide a reliable and efficient means to collect metering data withminimal human intervention. Furthermore, the system requires minimalhuman interaction to configure and upgrade efficiencies.

While systems and methods have been described and illustrated withreference to specific embodiments, those skilled in the art willrecognize that modification and variations may be made without departingfrom the principles described above and set forth in the followingclaims. For example, while communication server 122 has been describedas communicating with collectors 116 via a dial-up connection, thecommunication may take place wirelessly. Accordingly, reference shouldbe made to the following claims as describing the scope of disclosedembodiments.

1. In a network having a collector that receives data from nodes andcommunicates the data to a communication server, a method of registeringsaid nodes to communicate with said collector, comprising: initiating anode scan to establish communication between said collector and saidnodes; determining a reliability of a data communication path betweensaid collector and a node that responds to said node scan; andregistering said node if said node has a reliability above a firstpredetermined threshold; repeating said node scan at said collectormultiple times to insure all first level nodes that are capable ofreceiving said node scan have responded by comparing the number of nodesscans performed to a predetermined number of scans.
 2. The method ofclaim 1, further comprising: maintaining a database of nodes that have areliability below said first predetermined threshold.
 3. The method ofclaim 1, further comprising: initiating said node scan on apredetermined subset of said nodes.
 4. The method of claim 1, furthercomprising: determining said reliability in accordance with a receivedsignal strength value for said nodes that respond to said node scan. 5.The method of claim 4, wherein said first predetermined threshold is areceived signal strength value of −60 dBm.
 6. The method of claim 1,wherein registering a node that has a reliability above a predeterminedthreshold further comprises: updating a list of registered nodes at saidcollector to include said node being registered; and transmittingregistration information to said node.
 7. The method of claim 1, whereinupdating said list comprises updating at least one of a uniqueidentifier of said node, said data communication path to said node, anda level of said node in a subnet that communicates to said collector. 8.The method of claim 1, wherein transmitting registration information tosaid node comprises transmitting at least one of a unique identifier ofsaid collector, said data communication path to said collector, a levelof said node in a subnet that communicates to said collector, and asecond meter with which said meter should communicate.
 9. The method ofclaim 1, further comprising: performing said node scan at successivelyhigher level nodes beginning with said first level nodes through nth-1level nodes to register second level nodes through nth level nodes;updating a list of registered nodes in accordance with responses thatare received from said second level nodes through said nth level nodes;and transmitting registration information to said second level nodesthrough said nth level nodes.
 10. The method of claim 9, wherein saidcollector requests said successively higher level nodes to perform saidnode scan, and wherein said request comprises at least one of a numberof timeslots available for responding nodes, a unique address of saidcollector, a level within said subnet of the node sending the request,and said reliability of said data communication path.
 11. The method ofclaim 9, wherein updating said list comprises updating at least one of aunique identifier of said second level nodes through said nth levelnodes, said data communication path to said second level nodes throughsaid nth level nodes, and a level of said second level nodes throughsaid nth level nodes in a subnet that communicates to said collector.12. The method of claim 9, wherein transmitting registration informationto said second level nodes through said nth level nodes comprisestransmitting at least one of a unique identifier of said collector, saiddata communication path to said collector, a level of said second levelnodes through said nth level nodes in a subnet that communicates to saidcollector, and a second meter with which said meter should communicate.13. The method of claim 1, further comprising: determining a level ofsuccess in communicating with said node; and if said level of success isbelow a second predetermined threshold, instructing said node to respondto subsequent node scans.
 14. The method of claim 13, furthercomprising: changing a collector to which said node communicates to asecond collector in response to a subsequent node scan; qualifying saidnode wherein said second collector makes plural attempts to communicateto said node; and registering said node to said second collector if apredetermined number of said plural attempts to communicate aresuccessful.
 15. A network communication system comprising collectorsthat receive data from nodes registered with said collectors, and saidcollectors communicating the received data to a communication server, amethod of qualifying communication between said nodes and saidcollectors, comprising: maintaining a list of nodes registered with afirst collector; determining a level of success of communication betweena first node and said first collector; and if said level of success isbelow a predetermined threshold, instructing said first node to respondto subsequent node scans, wherein node scans are initiated by eachcollector to register nodes that are in communication with said eachcollector; changing a collector to which said first node communicates toa second collector in response to a subsequent node scan; qualifyingsaid node wherein said second collector makes plural attempts tocommunicate to said node; and registering said node to said secondcollector if a predetermined number of said plural attempts tocommunicate are successful; organizing said nodes into levels beginningwith a first level that communicate directly with said collectorsthrough nth level that communicate directly to an nth-1 level;performing said subsequent node scans at successively higher levelsbeginning with first level nodes through nth-1 level nodes to registersecond level nodes through nth level nodes; and updating a list ofregistered nodes in accordance with responses that are received fromsaid second level nodes through said nth level nodes.
 16. The method ofclaim 15, wherein said first node comprises any node among nodesorganized in said first level through nth level.